Low-temperature defrosting system



Oct 10, 1950 R. E. PABST 2,525,560

LOW TEMPERATURE DEF'ROSTING SYSTEM Filed Feb. 4, 1949 4 Sheets-Sheet 1 Richard E. Pabst,

ATTOR N EY- Oct. 10, 1950 R. z. PABST LOW TEMPERATURE DEF'ROSTING SYSTEM 4 Sheets-Sheet 5 Filed Feb. 4, 1949 II I I II I I I I I I II I IIIII. I III.I.I II II I I I II I I .I II II I I II II II III II II I I II I I I I I I I I I I I II I II I III I IIIII II II I I II I II II I I vwe/wtm, E. Pabst,

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7 Hzchard ATTORNEY- Oct. 10, 1950 R. E. PABST LOW TEMPERA'I'URE DEF'ROSTING SYSTEM 4 Sheets-Sheet 4 Filed Feb. 4, 1949 Z 5 a E M h. .0 Z R ATTORNEY Patented Oct. 10, 1950 now-'rnrrrenarnan naraos'rma srs'rau means a. Pabst, San Antonio, Tex, auignor to Ed Friedri pontion of Texas ch, Inc., San Antonio, Tex, a cor- Applicaflolr February 4, 1949, Serial No. 74,525

2 Claims.

My invention has for its object to provide a refrigerator with a cooling and defrosting system and means for circulating the cold air in the refrigerator only during the cooling period, 1. e., when the evaporator is being defrosted the air circulating blower is stopped.

Another object is to provide a time controlled electro-magnetically actuated reversing valve for reversing the connections between the compressor and the evaporator and condenser whereby at stated intervals and for predetermined time intervals the functions of the evaporator and condenser are reversed.

A further object is to provide an improved construction of reversing valve wherein the construction and operations of the parts are such that valve sticking is avoided and snap action is obtained.

Other objects will in part be obvious and in part be pointed out hereinafter.

To the attainment of the aforesaid objects and ends invention still further resides in the valve 3, the valves 2 and 3 being connected, in parallel, to the coil end l and to the'beginning or entrant end 4" of a pipe 4 which passes through a cylinder 6 and has its other end 4 passed into a receiver ii to extend below the liquid level therein (see Fig. 2). The other end of the evaporator coil I is connected to a pipe 5 which also passes through the cylinder 6 in proximity to the pipe 4 and continues to the port I8 of the reversing valve R. V. The portions of the pipes 4 and 5 which are 'containedwithin the cylinder 6 constitute therewith a heat exchanger. In practice the evaporator and heat exchanger are located in a partitioned of! space in the refrigerator case R as will later more fully appear.

The condenser C has one end 1 of its coil 1 connected to a one way check valve 8 and to a restrictorformed by a capillary tube 9. A pipe I!) has its inlet end Ill connected to the tube 9 w and to the valve 8 while its outlet end Ill passes novel details of construction, combination and arrangement of parts, all of which will be first fully described in the following detailed description, and then be particularly pointed out in the appended claims, reference being had to the accompanying drawing, in which:

Fig. 1 is a schematic view of the cooling, defrosting and air moving system embodying my invention.

Fig. 2 is a section on the line 2--2 of Fig. 1.

Fig. 3 is a vertical section of the improved reversing valve with the valve in the normal position, 1. e., in the position it assumes during the cooling period, the section being taken on the line 3-3 of Fig. 4.

Fig. 4 is a section on the line 4-4 of Fig. 3, with the valve in the reverse-cycle or defrostin position.

Fig. 5 is a top plan view of the valve on a smaller scale.

Fig. 8 is a cross section of a refrigerator of the type for which my cooling and defrosting system is particularly adapted, the section being taken on the line 8-0 of Fig. 7.

Fig. 'l is a section on the line 1-1 of Fig. 6.

In the drawings in which like numerals and letters of reference indicate like parts in all the figures, E represents the evaporator. C the condenser and R. V. the reversing valve of a reversecycle defrosting refrigerating system.

As shown in Fig. 1, the evaporator coil i has one end I connected to a thermostatically opgrated expansion valve I and to a one way check :uid level in the receiver.

into the receiver ll, terminating below the liq- The restrictor and the one way check valve 8 are connected in parallel with one another. The other end of the coil 1 connects with a pipe 1 that runs from the port IQ of the reversing valve.

l2 indicates the compressor, it the motor which drives it via a belt and pulley connection 14. The high side of the compressor is connected to a port 2| of the reversing valve by means of a pipe IS. The low side of the compressor is connected with ports 2n and 22 of the reversing valve via pipes I8 and H.

The construction of the reversing valve is best illustrated in Figs. 3, 4 and 5 by reference to which it will be seen that-the valve housing is a made in two parts 23 and 24 and ends 21 and 29. The several parts 23, 24, 21 and 219 have stepped engaging portions containing sealing rings 25, 25, 28 and are held together in fluid tight engagement by bolts and nuts 30 that pass through apertures in the end plates or heads 21 and 29.

The valve housing contains three chambers 3|, 32 and 33 and communicating passages 4|, li between the chambers. The port 22 communicates directly with chamber ill, the port l9 communicates directly with passage 4| and indirectly with chambers 31 and 32. The ends of the passage 4| are provided with valve seats 34 and 35 respectively.

The port 2! communicates directly with chamber 32 while the port it communicates directly with passage 4!? and only indirectly with charm 3 bers32 'and33. 'Port 26 communicates directly with chamber 33. 1 The ends of the passage 4| are provided with valve seats-36 and 31 respective A valve shaft 38 passes through the chambers and passages of the valve housing and projects above the top end plate or head 29. At its lower end a guide 26 is threaded on the rod as at 38* and pinned thereto as at 26. The guide 26 operates in a guide-way 21 in the lower head 21.

Mounted on the rod 28 are two one way valves 39, 46 and 45, 46, and one two way valve 42, 43, 44, the two way valve being intermediate the others. The upper and lower valves each are composed of a metal disc 39, 45 respectively and valve seat member 46, 46 respectively.

Securely mounted in an opening in the head 29 is a non-magnetic cylinder in which operates an upper guide 41 carried by the rod 38. Within the cylinder 5| and mounted for free movement along the axis of the cylinder, is an armature 52 of magnetic material through an aperture in which the rod 38 passes. The upper end of the armature is counterbored as at 53 and nuts 56 are secured on the rod within the counterbore. The several valves and the guides on the rod 38 are firmly spaced apart by spacing members 49 49', 49, 49 49 49 and washers 48, 48', 46, 48 48 as shown.

Embracing the cylinder is the spool 55 on which the energizing coil 56 is wound. The spool 55 is held on the cylinder immovably by the laminated magnetic field plates 54.

When the reversing valve is in its normal position valve 39, 46 seats on seat 34, valve 43, 44 seats on seat 36 while valve 42, 43 and valve 45, 46 are unseated. Therefore ports I9 and 2| are in communication, port I8 is in communication with port 26 (see Fig. 3). When, however, magnet 54, 56, 56 is energized and rod 38 raised, ports 22 and I9 are in communication as are also ports 2| and I8 (see Fig. 4).

In order to energize coil 56 when it is desired to defrost the evaporator I provide an electric circuit which includes power lines 51 from one of which a wire 64 leads to coil 56 and by a branch 62 to a time clock circuit controller 66. A wire 63 connects the time clock with the other line wire 51. The time clock circuit controller includes fixed contacts 66, 61 and a movable contact 6| cooperating with the contacts 66, 61 to close the circuit at predetermined times and hold it closed for a predetermined time. interval. Contact 66 is connected to coil 56 by a wire 65 while contact 61 is connected to the other line wire 51 by a wire 68. Thus when contact 6| engages contacts 66, 61 the magnet circuit is closed and core 52 will be sucked up farther into the cylinder 5|.

As magnet coil 56 becomes energized core 52 moves up a short distance before engaging the nuts 56 to raise rod 38. As the movement of the core is swift it will impact the nuts and drive the valves 39, 46 and 42, 44 off their seats. This is advantageous should the valves tend to stick. Conversely, when the magnet coil 56 is de-energized the core 52 will drop onto guide 41 and then move down with the guide and valve rod to restore the parts to their normal position.

As before intimated the evaporator is located in a partitioned space in the refrigerator B. By reference to Figs. 6 and 7 it will be seen that the refri erator case has a front wall 81 with a window 88, a back wall 84, bottom 2|, sides 86 with windows 86, a. canopy 94 luminary 36.

18 is a longitudinal partition spaced from the back wall 84, in which space the evaporator E and heat exchanger 4, 5, 6 are located.

The interior of the case is also divided by a horizontal partition 11 into an upper food chamber U and a lower food storage chamber L. The shelf 11 extends forwardly from the partition 19 but terminates short of the front wall of the case (see Fig. 6) and a down air passage is thus provided between the upper and lower chambers. 83 is a down air duct with a foraminous wall to assist in the downward passage of air should the openings in the food shelf 18 become covered. The lower chamber L is provided with a food shelf 92 and a door opening 89 and door 96.

The specific construction of the refrigerator case is not per se a part of the present invention. Means are provided for effecting the circulation of air by providing beneath the evaporator two horizontal partitions 86 and 8| to provide two longitudinal ducts from one side of the case to the other, the upper one 86 having finned openings beneath the evaporator (see Fig. 7). In this manner a high air pressure duct 82 and a low pressure or return duct 63 are provided. At one end of these ducts is located a suction blower 58 and its motor 59 the suction blower being connected to ducts 82 and 83 as shown in Fig. 7. The partition 19 has air outlets 19 to the upper chamber U and air inlets 19 from the lower chamber to the duct 83.

The circuit for motor 59 includes a wire 69 to wire 64 from one line wire 51, a wire 16 to the armature 1| of a relay, a contact 12 and wire 13. 68 to the other line wire 51. Normally armature 1| engages fixed contact 12. The coil 14 of the relay connects by wire 15 to wire 64' and by wire 16 to-wire 65. Thus when contacts 6|, 66, 61 are closed coil 14 will be energized and armature 1| lifted to open the circuit to the motor 59 and stop the blower. Thus no forced air circulation takes place via the food chambers U and L while the defrosting cycle is on.

From the foregoing description, taken in connection withthe accompanying drawings, it is thought that the construction, operation and advantages of the invention will readily appear to those skilled in the art.

What I claim is:

1. A reversing valve for reverse-cycle refrigerating systems having a receiver, a compressor, a condenser, and an evaporator, said valve including: a casing having four chambers, namely, a top chamber, a bottom chamber and two intermediate chambers, there being a passage between the top chamber and the adjacent intermediate chamber, a passage between the bottom chamber and the intermediate chamber adjacent the same, said intermediate chambers being in communication with one another, a valve seat at each end of said first mentioned passage, a valve seat at the juncture of the two intermediate chambers and a valve seat at the bottom end of the second mentioned passage, a valve stem in said casing with a single acting valve in the upper chamber, a double acting valve in the intermediate chamber that is adjacent the top chamber and a single acting valvein the bottom chamber, a duct connecting the top and bottom chambers together, a duct for connecting the upper interwith a mirror 96 and a mediate chamber with the compressor, a duct for,

connecting the first mentioned passage with the condenser. a. duct for connecting the lower and chamber with the low side of the compressor, a duct for connecting the lower intermediate chamber with the evaporator, a core having limited axial movement on said stem, and a solenoid for operating the core to raise the stem and valves from one position to the other.

2. In a refrigerating system, a defrosting valve which includes a casing having a top chamber, a bottom chamber and two directly communicating intermediate chambers with a valve seat between the same, a passage with a valve seat at each end for connecting the top chamber with the top intermediate chamber, a passage between the bottom intermediate chamber and the bottom chamber with a valve seat at the lower end of the last named passage, a valve stem in said casing carrying a one-way acting valve in the top chamber, a two-way acting valve in the top intermediate chamber and a one-way acting valve in the bottom chamber, a pipe directly connectin the top and bottom chambers, and a weighted core on said valve stem, and a solenoid coopera- 6 tive with said core to shift the valve stem and its valves in one direction, the same being shifted in the opposite direction by gravity, said casing having a port from the first mentioned passage to the exterior of the casing, a port from the top intermediate chamber to the exterior of the easing, and a port from the lower intermediate chamber to the exterior of the casing.

RICHARD E. PABST.

REFERENCES CITED UNITED STATES PATENTS Number Name Date 2,124,268 Williams July 19, 1938 2,178,445 W'arneke Oct. 31, 1939 2,281,770 Hoesel May 5, 1942 2,299,404 Newton Oct. 210, 1942 2,351,140 McCloy June 13, 1944 2,459,173 McCloy Jan. 18, 1949 

